A unique aspect of nuclear reactors, and a foremost safety consideration, is the inherent presence of radiation and radioactive materials. This highly significant condition requires the most strict design and safety conditions with respect to many components and functions of a nuclear reactor plant and imposes numerous requirements in operating and maintaining nuclear plants. For example, reactor components and related equipment which become significantly radioactive in service generally must be capable of long term, trouble free and positive functions, as well as being amenable to operation and maintenance by personnel in remote locations.
Steam depressurization and/or pressure relief and/or water injection valves are especially critical devices in any type of high pressure hot water and/or steam producing units, and when employed in a nuclear reactor plant the highest standards and demands must be applied to design and fabrication of such valves.
Various valve designs and operating modes have been proposed and considered in an effort to meet the stringent demands for such steam depressurization and water injection valves. The depressurization valves for the advanced reactor designs have greater reliability and enhanced maintenance/performance characteristics compared to existing valve designs.